Friday 8th May 2015
ALS is proud to announce a revolution in micro-organism identification utilising 'MALDI-TOF' technology. ALS is equally proud of the fact that they are the first food testing laboratory in the UK to have this service accredited by UKAS.
What is 'MALDI-TOF'?
The unique way in which bacteria divide (one cell splits down the middle producing two cells) means that all bacteria of a single species are identical in terms of size, shape, mass and in their ability to utilise different sugars and proteins to derive energy.
In the past, laboratories have used these differing biochemical reactions in order to identify different bacteria from one another. This method of identification works well, but can often take several days to complete.
The technology behind the 'MALDI-TOF' method allows for rapid identification based on established chemical methodology known as mass spectrometry.
The procedure involves mixing the colony with a suitable matrix material (Matrix Assisted), which is hen dried onto a metal plate and placed into the MALDI-TOF machine. A pulsed Laser causes Desoprtion of the molecules which are then Ionised. The ions are acclerated by an electric field within a vacuum tube and the time (Time Of Flight) for each ion to reach a detector is measured.
By refering the spectrum pattern or 'mass fingerprint' to a database of 755 species, an accurate identification can be obtained.
What are the benefits of MALDI-TOF?
- Improved consistency and traceability - The specific nature of the test will allow clients to build their own database which may prove helpful when tracing the common source of either environment or finished product contamination as different strains of one bacterial species will show similar peak patterns.
- Reduced turnaround times - In addition to high specificity of the test, a considerable advantage of this procedure over the traditional methods of identification is the rapidity of the test. Once the samples has been prepared, the time taken to achieve a full identification within the MALDI-TOF apparatus can be as little as 17 minutes rather than days, thus reducing the anxious wait for confirmation following a presumptive pathogen result.
Where is the analysis carried out?
ALS has installed the MALDI-TOF instrument in their state-of-the-art laborarory in Chatteris in Cambridgeshire, with slide preparations at its other UK sites in Carlisle, Mirfield, Sittingbourne and Trowbridge.
UKAS accredited service
The instrument manufacturer has validated the system to comply with FDA requirements. The software is also 21 CFR Part 11 compliant (criteria under which electronic records and electronic signatures are considered to be trustworthy, reliable and equivalent tp paper records).
ALS has conducted internal validation to comply with the ISO 17025 requirements and the method is now UKAS accredited for Listeria monocytogenes, innocua, welshmeri, grayi, seeligeri and ivanoii identification.
Please note that we are also able to carry out general micro-organisms identifications.
How do I use this service?
For further details please call our Customer Services Team at Chatteris on 01354 697028 or e-mail us at [email protected]